How to Adjust Rolling mill Speed Control System?

According to the deviation of the speed command “ Un* ’’ and the speed feedback “ Un ” , the output is the given signal “ Ui* ” of the current command (for the DC motor, controlling the armature current is controlling the electromagnetic torque, and the corresponding speed can be adjusted).

The ACR (current regulator) is adjusted according to the deviation of “ Un* ’ and current feedback “ Ui* ”, and its output is the control signal Uc of the UPE (of the power conversion device). Then adjust the output of the UPE, that is, the armature voltage of the motor. Since the rotation speed of the rolling mill cannot be abrupt, the armature current changes after the armature voltage changes, and the corresponding electromagnetic torque also changes, by Te-TL=Jdn/dt. As long as Te and TL are not equal to each other, the speed will change accordingly. The torque generated by the armature current and the load torque is balanced throughout the whole process, and the speed is stabilized after the rotation speed is constant.

In the double closed rolling mill ring speed control system, the speed always varies closely following the given amount. Therefore, the quality of the given power supply is an important part of ensuring the normal operation of the system. The high-precision rolling mill speed control system must have higher precision for given regulated power supply.

Therefore, when designing the system control scheme and formulating the control circuit, it is necessary to pay great attention to the design and selection of the regulated power supply. The stabilized power supply consisting of three-terminal integrated voltage regulator has the simple circuit, stable performance, reliable operation and convenient adjustment. It has gradually replaced discrete components and is widely used in production practice. This integrated voltage regulator should be used as much as possible in the system to ensure reliable operation of the rolling mill system. In order to prevent the difficulties caused by large-scale grid voltage fluctuations to the operation of the regulated power supply, constant voltage transformers have been widely used as power supply transformers for regulated power supplies.

Commonly used rolling mill speed detecting devices are various tachogenerators and pulse speed measuring devices. Since the DC speed measuring generator does not need another rectifier device and no residual voltage, the DC speed measuring signal is widely used in the DC speed regulating the system to convert the speed into voltage.